CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 62/068,836, filed October 27, 2014, and U.S. Provisional Patent Application No. 62/208,279, filed August 21, 2015, each of which is incorporated herein by reference in their entirety as if fully set forth herein.

BACKGROUND

Field of the Invention

[0002] The present invention relates generally to systems and methods for securing shipping containers during transportation, and more particularly to, but not by way of limitation, to a fully automatic locking device.

History or the Related Art

[0003] In the shipping industry, goods are often packed into large metal containers called shipping containers. Shipping containers are commonly stacked on top of one another, below and above deck, in order to fit more shipping containers onto a shipping vessel to maximize an amount of cargo transported. To increase stability of the stacked (above deck) shipping containers and to increase the safety of stacked shipping containers, locking devices that are often referred to as twistlocks are used to interconnect two shipping containers together.

[0004] Each shipping container contains eight corner castings that are located at each of the shipping container's eight corners. Corner castings are standardized pockets that include openings called ISO holes. When stacking shipping containers, a locking device is inserted into each of the four bottom corner castings of the shipping container that is being stacked on top of a previously placed shipping container. With locking devices inserted into each of the four bottom corner castings, the shipping container is then lowered onto the previously placed shipping container. There are three general types of locking devices: manual, semi-automatic, and fully automatic. A manual locking device requires a user to manually lock and unlock the locking device. A semi-automatic locking device is automatically closed by the motion of loading a shipping container onto another shipping container, but must be manually unlocked for unloading. A fully automatic locking device does not require the user to lock or unlock the device during loading and unloading. [0005] The dimensions of corner castings of shipping containers can vary. Often times, due to wear from repeated use and/or high loads, corner castings can become deformed over time, which alters the dimensions of the corner castings. The dimensions can also vary somewhat based on upon inconsistent manufacturing processes. A consequence of these variances is that the variances can affect an ability of a twistlock to satisfactorily secure two shipping containers together. If the dimensions of a corner casting have been dramatically altered, the twistlock may fail to secure the two shipping containers under excessive loads. The locking devices disclosed herein are capable of working with a wider range of corner casting dimensions. This is due, in part, to the "floating" S-hook design, which allows the S- hook to move around within a housing to situate itself into a favorable gripping position within the upper and lower corner castings.

SUMMARY

[0006] The present invention is directed to an apparatus and method for securing two structures, such as shipping containers, together. The apparatus is a locking device that includes an s-hook. The s-hook includes a body portion that may include one or more hooks. For example, the body portion may include a first hook disposed at a first end of the body portion and extending in a first direction and a second hook disposed at a second end of the body portion and extending in a second direction that is opposite the first direction. The locking device also includes a housing that may include an internal cavity that is formed to accommodate one or more internal components, such as, for example, the s-hook and a handle assembly. The housing may also include a load pad. The internal cavity allows the s- hook to be movably secured within the housing. In some embodiments, the housing may include a first upper hook disposed on a first end of the housing and extending in the second direction. In some embodiments, the housing may include a second lower hook disposed on a lower end of the housing and extending in the first direction. In some embodiments, the S- hook includes an upper hook member and a lower hook member that is movably secured to the upper hook member to allow relative movement between the upper hook member and the lower hook member. In some embodiments the upper hook member comprises a notch disposed on a lower end of the upper hook member, and the lower hook member comprises a channeled portion adapted to receive the notch to movably secure the upper hook member to the lower hook member. In some embodiments, the locking device may include a hook that is pivotally secured to the housing and extends in the second direction. [0007] A method of using the locking device described above includes inserting a first portion of the device into a corner casting of an upper container, after which the upper container may be lowered onto a lower container so that a second portion of the device enters a corner casting of the lower container. The method may further include placing the locking device into a vertical tandem lifting mode by sliding a pin into locking engagement with the S-hook to prevent an opening or releasing movement of the S-hook. After the S-hook has been set into the vertical tandem lifting mode, the upper container may be lifted, which lifting also lifts the lower container.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

[0009] FIGURE 1 is a perspective view of an upper shipping container and a lower shipping container in a stacked arrangement;

[0010] FIGURE 2 shows two perspective views of a locking device according to an embodiment of the present invention;

[0011] FIGURE 3 A is an exploded assembly of a locking device from a first perspective according to an embodiment of the present invention;

[0012] FIGURE 3B is an exploded assembly of the locking device of FIGURE 3 A from a second perspective according to an embodiment of the present invention;

[0013] FIGURE 4 illustrates a coning/deconing process for a locking device according to an embodiment of the present invention;

[0014] FIGURE 5 is a side view of two locking devices installed into an upper and lower corner castings according to an embodiment of the present invention;

[0015] FIGURES 6 A and 6B illustrate a container-unloading process for a locking device according to an embodiment of the present invention;

[0016] FIGURES 7 shows three views of a locking device according to an embodiment of the present invention;

[0017] FIGURE 8 shows two perspective views of a locking device according to an embodiment of the present invention;

[0018] FIGURE 9 is an exploded assembly of the locking device of FIGURE 8 according to an embodiment of the present invention; [0019] FIGURE 10 illustrates three modes of a locking device according to an embodiment of the present invention; and

[0020] FIGURES 11 A, 11B, 11C, and 11D illustrate a container-unloading process for a locking device according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0021] As will be appreciated by those skilled in the art, shipping containers come in standardized sizes and contain standardized corner castings. For convenience, the figures discussed herein do not show the structure of the shipping container itself, but instead depict only the corner castings. It should be understood that the corner castings shown in the figures are a part of a shipping container. For purposes of this disclosure, the terms "short side" and "long side" are used to describe relative locations of shipping containers. For example, a "short side" of a shipping container refers to one of the two ends of a shipping container. A "long side" refers to one of the two sides of a shipping container, which are typically much longer in length (generally either 20 or 40 feet long) than the ends of a shipping container. When viewing a short side of the shipping container, the lower left corner casting is commonly referred to as the left-side corner casting and the lower right corner casting is commonly referred to as the right-side corner casting. The opposite short side of the shipping container also has a left-side corner casting and a right-side corner casting. Because of the symmetry, it can be seen that discussing one left-side corner casting necessarily describes the left-side corner casting of the opposite short side of the shipping container. The same is true for the right-side corner castings. For simplicity sake, the description below will refer to one short side of the shipping container unless noted otherwise.

[0022] In the following description, reference is made to directions (e.g., left, right, up, down, clockwise, and counter-clockwise). Such references are made with respect to the Figure being discussed unless otherwise specified. FIGURE 5 includes arrows 1-4 that represent left, right, upwards, and downwards directions. Though not included on other figures, these arrows 1-4 may be used with respect to other figures to reference relative directions. Arrow 1 generally indicates a "first direction." Arrow 2 generally indicates a "second" direction. Arrow 3 generally indicates an "upward direction." Arrow 4 generally indicates a "downward direction."

[0023] Referring to FIGURE 1, an upper shipping container 10 is shown above a lower shipping container 20. The upper shipping container 10 and the lower shipping container 20 each include a corner casting 14 at each of their eight corners. The upper shipping container 10 includes a long side 16 and a short side 18. The lower shipping container 20 includes a long side 26 and a short side 28. In order to secure the upper shipping container 10 to the lower shipping container 20, a locking device (e.g., a locking device 100 of FIGURE 2) is inserted into each of the upper shipping container's 10 bottom corner castings 14. The upper shipping container 10 may be secured to the lower shipping container 20 by lowering the upper shipping container 10 onto the lower shipping container 20 so that lower portions of the locking devices enter upper corner castings 14 of the bottom shipping container 20. If the locking devices are manual locking devices, a user must manually lock each locking device to secure the two shipping containers to one another. Likewise, a user must manually unlock the devices to unsecure the two shipping containers. If the locking devices are semi-automatic locking devices, the locking devices are automatically locked by the motion of loading the upper shipping container 10 onto the lower shipping container 20, but the semi-automatic locking devices must be manually unlocked for unloading. If the locking devices are fully automatic locking devices, a user is not required to lock or unlock the fully automatic devices during a loading or unloading process.

[0024] Referring now generally to FIGURE 2 and FIGURES 3A and 3B, an embodiment of a locking device 100 is shown from two perspectives. The locking device 100 comprises a housing 102 and an S-hook 150. The housing 102 comprises an internal cavity 103, a load pad 104 with an upper face 106 and a lower face 108. When the locking device 100 is installed between an upper and lower shipping container, the load pad 104 acts as a spacer upon which the upper shipping container rests (e.g., see FIGURE 5 A). The load pad 104 handles all of the weight of the upper shipping container so that the S-hook 150 is not loaded by the weight of the upper shipping container.

[0025] In the embodiment shown in FIGURE 2 and FIGURES 3A and 3B, the housing 102 includes a pair of hooks 110 and a pair of hooks 112. The pair of hooks 110 extends from an upper neck portion 114 of the housing 102. The upper neck portion 114 includes a pair of surfaces 116 and a pair of surfaces 118 that help restrict movement of the upper shipping container. In a typical embodiment, a distance between the pair of surfaces 116 and the pair of surfaces 118 is set to be slightly narrower than a width of an ISO hole of a corner casting. The pair of hooks 112 extends from a lower neck portion 120 of the housing 102. The lower neck portion 120 includes a pair of surfaces 122 and a pair of surfaces 124 that help restrict movement of the upper shipping container. In a typical embodiment, a distance between the pair of surfaces 122 and the pair of surfaces 124 is set to be slightly narrower than a width of an ISO hole of a corner casting. In some embodiments, the surfaces 116, 118, 122, and 124 are generally perpendicular to the upper face 106 of the load pad 104.

[0026] The pair of hooks 110 extend from the housing 102 in a first direction (e.g., see arrow 2 in FIGURE 5), and the pair of hooks 112 extend from the housing 102 in a second direction that is the opposite direction relative to the first direction (e.g., see arrow 1 in FIGURE 5). The pair of hooks 110 and the pair of hooks 112 interact with an interior of an upper and lower corner casting, respectively, to help secure two shipping containers together. The function of the pair of hooks 110 and the pair of hooks 112 will be discussed in more detail below. In other embodiments, the locking device 100 may include a housing that does not include either of the pair of hooks 110 or the pair of hooks 112 (e.g., see FIGURE 8). In other embodiments, the locking device 100 may include a housing that includes either the pair of hooks 110 or the pair of hooks 112 (e.g., see FIGURE 7). In other embodiments, a single hook 110 and/or a single hook 112 may be used.

[0027] In a typical embodiment, the housing 102 includes a handle assembly 130. The handle assembly includes a handle 132, a mouth piece 134, a spring 136, a pin 138 (best seen in FIGURES 3A and 3B). Pulling the handle 132 causes the pin 138 to slide with a housing groove 139, which sliding changes a mode of operation for the locking device 100. When the handle 132 is in a first position (i.e., the position shown in FIGURE 2), the locking device is in an automatic mode. In the automatic mode, the pin 138 limits a rotational movement of the S-hook 150 within the housing 102. In the automatic mode, the pin 138 is positioned in a pin-recess of the S-hook 150 that is formed between the upper hook 154 and the stop 160. As shown in FIGURE 3 A, when the pin is positioned in the pin-recess, a range of motion of the S-hook 150 is limited. Limiting movement of the S-hook 150 may be desirable to provide fall-out protection so that the locking device cannot fall out of a lower corner casting of an upper shipping container while the upper shipping container is in the process of being moved by, for example, a crane.

[0028] In some embodiments, the spring 136 can be included to bias the handle 150 into the first position. In some embodiments, the handle 132 may be placed into a second mode by pulling the handle 132 away from the housing 102. In order to keep the locking device 100 in the second mode, a user must hold onto the handle 132, otherwise the spring 136 would retract the handle back into the automatic mode. In the second mode, the pin 138 has been retracted from the pin-recess and no longer restricts rotational movement of the S- hook 150 within the housing 102. In the second mode, the S-hook 150 is allowed a greater range of motion within the housing 102, which allows the locking device 100 to be removed from the lower corner casting of the upper shipping container.

[0029] In some embodiments, the handle 132 may be placed into a third mode by pulling the handle 132 out away from the housing 102 and securing a swage in a notch of the mouthpiece 134 to keep the handle 132 retracted (similar to the handle assembly 630 discussed below). In the third mode, a pin (similar to pin 640) greatly limits the S-hook 150 from moving. The third mode effectively locks the locking device 100 so that application of an evenly distributed vertical force, for example by a crane, will not disengage the locking device 100 from the lower shipping container. In this manner, two shipping containers can be lifted at the same time.

[0030] The S-hook 150 comprises a body portion 152 (best seen in FIGURES 3A and 3B) that resides within the housing 102. An upper hook 154 extends from a first end of the body portion 152 and a lower hook 156 extends from a second end of the body portion 152. As shown in FIGURE 2, the upper hook 154 generally extends in a direction opposite to the pair of hooks 110, and the lower hook 156 extends in a direction opposite to the pair of hooks 112. When inserted into an upper corner casting, the upper hook 154 contacts an inner surface of the upper corner casting to help secure the locking device 100 to the upper corner casting. When inserted into a lower corner casting, the lower hook 156 contacts an inner surface of the lower corner casting to help secure the locking device to the lower corner casting.

[0031] In some embodiments, the S-hook 150 includes a first stop 158 and a second stop 160 (best seen in FIGURE 3B). The first stop 158 and second stop 160 are positioned to contact an exterior surface of an upper corner casting and an exterior surface of a lower corner casting, respectively, to prevent rotation of the S-hook 150 in certain situations (e.g., when an upper shipping container experiences a shearing force that would cause the S-hook 150 to rotate or tilt in a counter-clockwise direction). The function of the first stop 158 and the second stop 160 will be discussed in more detail below.

[0032] In some embodiments, it is desirable to increase a width of the upper hook 154 and the lower hook 156 to increase a size of a point of contact between the upper hook 154 and the lower hook 156 with interior surfaces of an upper and lower corner casting, respectively. Increasing the size of the point of contact helps distribute forces applied by the upper hook 154 and the lower hook 156 to the corner castings, which distribution reduces a likelihood that the corner castings will be plastically deformed by the S-hook 150. In other embodiments, the point of contact may be increased by optimizing a shape of the upper hook 154 and the lower hook 156. For example, the upper hook 154 could include a planar or close to planar flat portion that contacts the interior wall of the corner casting. In other embodiments, plates could be pivotally or hingedly mounted to the upper hook 154 and the lower hook 156. Allowing the plates to pivot ensures, regardless of variances in dimensions of the corner castings, that the plates squarely contact the inner wall of the corner casting.

[0033] In some embodiments, it is desirable to maximize a length or reach of the upper hook 154 and the lower hook 156. Maximizing the reach of the upper and lower hooks allows the upper and lower hooks to grip farther into the corner casting and farther from an edge of the ISO hole. Gripping the interior wall of the corner casting farther from the edge of the ISO hole is desirable because the strength of the interior wall increases as a distance between the ISO hole and the upper and lower hook increases.

[0034] In some embodiments, the housing 102 does not include a load pad 104. In one embodiment without a load pad 104, the upper shipping container could instead rest upon flanges that extend from the body portion 152 of the S-hook 150. For example, the stops 158 and 160 could be used in place of the load pad 104. In such an embodiment, the upper shipping container would be supported by the interfaces between the stop 158 with a chamfered edge of an ISO hole of a lower corner casting, and the interface between the stop 160 with a chamfered edge of an ISO hole of an upper corner casting. In another embodiment, additional stops could added the body portion 152 to provide additional contact points between the S-hook 150 and the upper and lower shipping containers.

[0035] Referring now to FIGURES 3A and 3B, the locking device 100 of FIGURE 2 is shown as an exploded assembly from a first and second perspective, respectively. As shown in FIGURES 3A and 3B, the housing 102 is made up of a housing component 102(1) and a housing component 102(2). Splitting the housing 102 into the housing components 102(1) and 102(2) makes it possible to place the S-hook 150 within the housing 102. In one embodiment, the housing components 102(1) and 102(2) may be secured to one another with screws 126. In other embodiments, the housing components 102(1) and 102(2) may be secured to one another by other known fastening mechanisms, such as, for example, welding, mating grooves, and the like. In another embodiment, the housing 102 could be broken into different components as desired.

[0036] The S-hook includes a face 162 disposed above the first stop 158 and a face 164 disposed below the second stop 160. The faces 162 and 164 interact with ISO holes of upper and lower corner castings, respectively, to limit an amount of movement of the S-hook 150 when the locking device 100 encounters a vertical load. The interaction of the faces 162 and 164 will be discussed in more detail below.

[0037] Referring now to FIGURE 4, three exemplary stages (l)-(3) of a deconing process for a locking device 200 are illustrated. Starting with stage (1), the locking device 200 is shown installed or "coned" in an upper corner casting 202. The upper corner casting 202 is a part of an upper shipping container (e.g., the upper shipping container 10). The upper corner casting 202 includes an exterior surface 204, an ISO hole 206, and an interior surface 208. In the coned position, an upper hook 210 of an S-hook 212 contacts a first side of the interior surface 208 and a pair of hooks 220 of a housing 222 contacts the a second side of the interior surface 208. In this position, the upper hook 210 and the pair of hooks 220 have a width W that is larger than a width of the ISO hole 206, thus retaining the locking device 200 within the upper corner casting 202.

[0038] Referring now to stage (2) of FIGURE 4, in order to remove the locking device 200, a user pulls a handle (e.g., the handle 132 of FIGURE 2) to move a pin (e.g., the pin 138) out of restrictive engagement with the S-hook 212. Once the pin has been moved, the S-hook 212 is permitted to rotate or tilt in a clockwise direction relative to the housing 222. Rotation of the S-hook 212 reduces the width W between the upper hook 210 and the pair of hooks 220.

[0039] Referring now to stage (3) of FIGURE 4, when the width W has been reduced to a value less than the width of the ISO hole 206, the locking device 200 may be removed from the upper corner casting 202 (e.g., see FIGURE 4C). Once the locking device 200 has cleared the ISO hole 206, the user may release the handle. Coning the locking device 200 works in substantially the same way, but in reverse order. A user pulls the handle and collapses the hook 210 relative to the pair of hooks 220 to reduce the width W a sufficient amount to insert the hook 210 and the pair of hooks 220 into the ISO hole 206. Once the hook 210 and the pair of hooks 220 have been pushed into the ISO hole 206, the user can release the handle to permit the hook 210 and the pair of hooks 220 to become secured within the upper corner casting 202.

[0040] Referring now to FIGURE 5, a locking device 300(1) is shown secured to an upper corner casting 302 and a lower corner casting 303. As will be appreciated by those having skill in the art, the upper corner casting 302 is a part of an upper shipping container (e.g., the shipping container 10), and the lower corner casting 303 is a part of a lower shipping container (e.g., the lower shipping container 20). The upper corner casting 302 includes an exterior surface 304, an ISO hole 306, and an inner surface 308. The lower corner casting 303 includes an exterior surface 305, an ISO hole 307, and an inner surface 309. The locking device 300(1) is secured to the upper corner casting 302 by an upper hook 320 of an S-hook 322 and a pair of hooks 324 of a housing 326. The upper hook 320 and the pair of hooks 324 have a width X that is wider than a width of the ISO hole 306. Similarly, the locking device 300(1) is secured to the lower corner casting 303 by a lower hook 328 of the S-hook 322 and a pair of lower hooks 330 of the housing 326. The lower hook 328 and the pair of hooks 330 have a width Y that is wider than a width of the ISO hole 316.

[0041] While transporting shipping containers across, for example, the ocean, a ship may encounter varying degrees of rough waters that cause the ship to encounter forces, such as, for example, roll, pitch, surge, yaw, and heave. As the ship experiences, for example, rolls and pitches, shipping containers on the ship will undergo different loading scenarios. A basic scenario that may be encountered is that one side of a shipping container will experience a lifting force and the opposite side of the shipping container will experience a compressive force. When this scenario is encountered, the locking device 300(1) prevents the side of the container that experiences the lifting force from detaching from the container below.

[0042] Still referring to FIGURE 5, arrow 3 indicates the direction of a force applied to the upper corner casting 302. For the purposes of this discussion, it is assumed that the opposite side corner casting is under compression. The locking device 300(2) that is located in the opposite side corner casting acts like pin that limits lateral movement of the upper shipping container relative to the lower shipping container. The locking device 300(2) is not dependent on the presence of a compressive force to restrict lateral movement of the upper shipping container. If the force lifting the upper corner casting 302 is strong enough, the upper corner casting 302 will begin to move upwards relative to the lower corner casting 303. This upward movement is limited by the locking device 300(1). As the upper corner casting 302 begins to move upwards, the movement attempts to tilt the S-hook 322 in a clockwise direction. If the S-hook were permitted to continue to tilt, the widths X and Y could be reduced enough to permit the locking device 100 to slip out of the ISO holes 306 and 316. This rotation is, however, prevented by the faces 162 and 164. As the S-hook 322 is urged to tilt in a clockwise direction, the face 362 bears against a right side of the ISO hole 306 and the face 364 bears against the left side of the ISO hole 316. Similarly, the housing 326, if unstopped, would attempt to tilt in a counter-clockwise direction. The counter-clockwise tilting of the housing 326 is limited by load pad 328, face 332 (similar to the face 118), and face 334 (similar to the face 122). As the housing 326 begins to tilt, the load pad 328 bears against the exterior surface 304, the face 332 bears against a left side of the ISO hole 306, and the face 334 bears against the right side of the ISO hole 307. In this manner, the locking device 300 is able to maintain a secured connection to the upper corner casting 302 and the lower corner casting 303.

[0043] The process described above with respect to FIGURE 5 is done by way of example. As a ship travels across the ocean, various conditions could be encountered such that various combinations of loads are encountered by shipping containers stored on the ship. The locking devices discussed herein are designed to maintain a secured connection between an upper shipping container and a lower shipping container so long as at least one corner of the upper shipping container does not experience a load that would raise that one corner upwards relative to the corresponding corner casting of the lower shipping container.

[0044] Referring now to FIGURES 6 A and 6B, a discharge sequence of an upper shipping container is shown. By way of example, four stages (l)-(4) of the discharge sequence are shown. Stage (1) of FIGURE 6A shows a side view of a locking device 400 in an automatic mode installed an upper corner casting 402 and a lower corner casting 403. The upper corner casting 402 is associated with an upper shipping container (e.g., the upper shipping container 10 from FIGURE 1), and the lower corner casting 403 is associated with a lower shipping container (e.g., the lower shipping container 20 from FIGURE 1). The upper corner casting 402 includes an exterior wall 404, an ISO hole 406, and an interior wall 408. The lower corner casting includes an exterior wall 405, an ISO hole 407, and an interior wall 409.

[0045] The process of unloading a shipping container is accomplished attaching a lifting device, such as a crane, to the upper shipping container and lifting with an upward force that lifts each of the upper shipping container's corner castings. This upwards movement of the upper shipping container is different compared to the upwards movement of the upper shipping container discussed in FIGURE 5, because the upward movement discussed in FIGURE 5 only occurred on one side of the upper shipping container. By contrast, the upward movement of the upper shipping container shown in FIGURES 6A and 6B occurs at each of the upper shipping container's four corner castings. As a result, none of the locking devices 400 act as pins that restrict lateral movement of the upper shipping container. Because lateral movement of the upper shipping container relative to the lower shipping container is no longer restrained, a width V of locking device 400 is reduced as the upper shipping container continues to move upwards. As the upper shipping container continues to move upwards, the width V reduces to a value less than the width of the ISO hole 407 and the upper shipping container has been removed from the lower shipping container. The geometries of the S-hook 422 and the housing 426 are formed, as shown, to enable this movement. This process will be discussed in more detail below. As the upper shipping container is moves upward, each locking device 400 that is situated in each of the four lower corner castings of the upper shipping container reacts in a similar way. To simplify the discussion of the unloading process, only one of the four locking devices 400 will be discussed.

[0046] Referring now to stage (1) of FIGURE 6 A, the locking device 400 is shown just before the upper shipping container is lifted upwards. In this resting position, the upper corner casting 402 rests upon a load pad 427 of the housing 426. An upper hook 420 of an S- hook 422 is shown in contact with the interior wall 408 of the upper corner casting 402 and a pair of hooks 424 of the housing 426 is shown in contact with the interior wall 408 on an opposite side of the ISO hole 406. A width Z indicates a reach or span of the upper hook 420 and the pair of hooks 424. The width Z is shown to be wider than a width of the ISO hole 406. A lower hook 428 of the S-hook 422 is shown in contact with the interior wall 409 and a pair of hooks 430 of the housing 426 is shown in contact with the interior wall 409 on an opposite side of the ISO hole 407. The width V indicates a reach or span of the lower hook 428 and the pair of hooks 430. The width V is shown to be wider than a width of the ISO hole 407.

[0047] Referring now to stage (2) of FIGURE 6A, the locking device 400 is shown just after the upper shipping container begins to move upwards from the lower shipping container. Once the upper shipping container begins to move upwards relative to the lower shipping container, the width Z between the hook 420 and the pair of hooks 424 has reduced slightly. The reduction in width Z results from reactionary movements of the S-hook 422 and the housing 426. As the upper corner casting 402 moves upwards, (2) of FIGURE 6A shows that the hook 420 has moved closer to the left edge of the ISO hole 406 and the pair of hooks 424 has moved closer to the right edge of the ISO hole 406. However, the movement of the hook 420 and the pair of hooks 424 is limited by interaction of a face 432 (similar to face 162) of the S-hook 422 with a right side of the ISO hole 406 and a face 434 (similar to face 164) with a left side of the lower ISO hole 407, which ensures that the width Z remains larger than the width of the ISO hole 406. In contrast to the width Z, the width V has been reduced by a larger amount. This is due, in large part, to the movement of the pair of hooks 430 relative to the ISO hole 407. As the upper corner casting 402 moves upwards, an upper slope 436 of the pair of lower hooks 430 contacts a bottom edge of the lower ISO hole 407, which causes the pair of lower hooks 430 retract inwards relative to the bottom edge of the lower ISO hole 407. The contact between the upper slope 436 and the bottom edge of the lower ISO hole 407 also displaces the upper container towards the right (best shown in stage (1).

[0048] Referring now to stage (3) of FIGURE 6B, the locking device 400 is shown after continued upward movement of the upper shipping container. As the upper shipping container continues upwards, the upper shipping container also continues to move towards the right. Once a face 438 (similar to face 122) of the housing 426 has cleared a right edge of the lower ISO hole 407, the upper shipping container is able to move sufficiently far to the right to permit the S-hook 422 to continue to pivot in the clockwise direction. The S-hook 422 essentially pivots about a point of contact between the hook 420 and the interior wall 408. This pivoting motion results in lateral movement of the lower hook 428 towards the lower ISO hole 407.

[0049] Referring now to (4) of FIGURE 6B, the locking device 400 is shown exiting the lower corner casting 403. As the upper shipping container continues its upward and lateral movement from (3) above, the S-hook 422 continued to pivot about the point of contact with the interior wall 408, and the lower hook 428 continued to move towards the lower ISO hole 407 until the width V had been reduced enough to permit the locking device 400 to exit the lower ISO hole 407. As noted above, a similar process happens on an opposite side of the upper shipping container. Due to the symmetry of the reactions, the opposite side of the upper shipping container moves to the left, which causes the upper shipping container to, in this instance, rotate in a counter-clockwise direction about its vertical axis.

[0050] Still referring to stage (4) of FIGURE 6B, it can be seen that a loading process works in a similar manner. As the upper shipping container is lowered towards the lower ISO hole 407, a cone 440 is directed towards the lower ISO hole 407. The cone 440 includes angled faces to help guide the upper shipping container into the lower ISO hole 407.

[0051] Referring now to FIGURE 7, multiple views of a locking device 500 are shown. The locking device 500 is similar to the locking device 100 and includes similar features, such as, for example, similar surfaces disposed on the housing 502 and the S-hook 550. The locking device 500 includes an S-hook 550 that is movably secured within a housing 502. The S-hook 550 includes an upper hook 554 and a lower hook 556. The housing 502 includes a load pad 504, a hook 512, and a handle assembly 530. In contrast to the locking device 100, the pair of hooks 112 have been replaced with a single hook 512. The pair of hooks 114 has been removed. The housing 502 is configured to permit the S- hook 550 to articulate within the housing 502 so that the upper hook 554 and the lower hook 556 are permitted to engage and disengage an inner portion of a corner casting, similar to discussion of the locking device 300 in FIGURE 5. In one aspect, tolerances within the housing permit the S-hook to both tilt/rotate and "float" within the housing. The term "float" is used to generally convey that the S-hook 550 has some freedom to move vertically within the housing.

[0052] As shown in FIGURE 7, the locking device 500 is in an automatic mode. In the automatic mode, the handle is in the position shown. In a typical embodiment, the handle assembly 530 operates in much the same way as the handle assembly 130 to enable a user to select the automatic mode, a second mode for coning/deconing, and a vertical tandem lifting mode.

[0053] Referring now to FIGURE 8, two views of a locking device 600 according to one embodiment are shown. The locking device 600 includes a housing 602, an S-hook 650, and a hanger 670. The housing 602, similar to housing 102 and housing 502, may include a first housing component 602(1) and a second housing component 602(2) to facilitate assembly of the locking device 600. The housing 602 forms an internal cavity 603 that accommodates, for example, the S-hook 650 and the handle assembly 630. In contrast to the housing 102 and the housing 502, the housing 602 does not include an upper housing hook or a lower housing hook. The housing 602 includes a load pad 604 that is similar to the load pad 104 and the load pad 504. The housing 602 further includes a surface 616 and a surface 618, which faces are similar to faces 116 and 118, respectively. Faces 616 and 618 interact with an ISO hole in a similar manner as faces 116 and 118. The housing 602 also includes a handle assembly 630, which is similar to the handle assembly 130.

[0054] The S-hook 650 comprises an upper hook member 652 and a lower hook member 654. The upper hook member 652 includes a notch 656 that movably couples with a channeled portion 658 of the lower hook member 654 (best seen in FIGURE 9). The coupling of the upper hook member 652 with the lower hook member 654 permits the upper hook member 652 to move independently of the lower hook member 654, and vice versa. The upper hook member 652 includes a hook 660 (best seen in FIGURE 9) that extends in a first direction. The hook 660 is similar to the upper hook 152. The upper hook member 652 also includes a tab 662 that interacts with the handle assembly 630 to control a range of motion of the S-hook 650. The lower hook member 654 includes an upper hook 664 that extends in an opposite direction as the hook 660 and a lower hook 666 that extends in the same direction as the hook 660. The lower hook member 654 also includes a cone portion 668 that helps to guide the locking device into a corner casting of a lower shipping container.

[0055] The hanger 670 includes a pair of tabs 672 that engage a pair of corresponding pockets 674 in the housing 602 to permit the hanger 670 to pivot about the pair of tabs 672. The hanger 670 also includes a hook 674 that extends in a direction opposite to the hook 660. The hook 674 is adapted to engage an interior wall of an upper corner casting. In some embodiments, a torsional spring may be used to bias the hanger 670 so that the hook 674 is biased to rotate or tilt away from the hook 660. Biasing the hanger 670 may help ensure good contact between the hook 674 an interior wall of the upper corner casting.

[0056] Referring now to FIGURE 9, an exploded assembly of the locking device 600 is shown. The locking device 600 includes a handle assembly 630 that includes a handle 632, a mouthpiece 634, a spring 636, a spring 638, and a pin 640. The handle 632 is coupled to the pin 640 via a wire 642. The mouthpiece 634 comprises a pair of tabs 644 that mate with a pair of recesses 646 that are formed into the housing 602. The mouthpiece 634 also includes a slot 635 that is adapted to receive a swage 643 of the wire 642. Operation of the handle assembly 630 will be discussed in more detail below.

[0057] Referring now to FIGURE 10 illustrates three user-selectable modes for the locking device 600(1). The locking device 600(1) illustrates an automatic mode. In order to provide a better view of interior of the locking device 600(1), the housing component 602(1) has been hidden. In the automatic mode, the locking device 600(1) is configured so that a user is not required to lock or unlock the locking device 600(1) during loading and unloading of a shipping container. The handle 632 is shown in its default position. When the handle is in the default position, the pin 640 is positioned as shown with a recess 641 lined up with the tab 662 of the upper hook member 652, which alignment allows the upper hook member 652 to pivot, but prevents the hanger 670 from pivoting about the pair of tabs 672. The hanger 670 is prevented from moving due to an interference between a tab 673 and the pin 640. By preventing the hanger 670 from rotating, the locking device 600(1) is secured in the upper corner casting. This is particularly important when a shipping container is being carried by crane into position above another shipping container. If a locking device were to fall from a shipping container when being moved into position, it is possible that it could strike a workman or cause other damage. Locking the hanger 670 provides fallout protection.

[0058] The locking device 600(2) illustrates a coning/deconing mode. In order to provide a better view of interior of the locking device 600(2), the housing component 602(1) has been hidden. As shown, the handle 632 is in the extended position. In this mode, the pin 640 is retracted. When the pin 640 is retracted, the tab 673 is no longer obstructed and the hanger 670 is free to pivot into an open position as shown. With the hanger 670 retracted, the locking device 600(2) may be inserted into or removed from a corner casting. In order to place the fully automatic twistlock into the coning/deconing mode, a worker grabs the handle and pulls it out away from the housing 602. For coning, the worker pulls the handle and then pushes the locking device 600(2) into an upper corner casting with the handle pointing out away from an interior portion of the shipping container. In this way, the position of the handle 632 helps identify a proper orientation for installing the locking device 600(2), thereby reducing the possibility that a worker could install the locking device 600(2) in the wrong orientation. As the locking device is pushed into the upper corner casting, the hanger 670 may contact an edge of the ISO hole of the upper corner casting. However, because in the coning/deconing mode the pin 640 is not restricting the movement of the hanger 670, the hanger 670 can pivot out of the way of the edge of the ISO hole to permit the fully locking device 600(2) to be inserted into the upper corner casting. Once the upper hook member 652 and the hanger 670 have been pushed up into the upper corner casting, the hanger 670 will rotate or tilt back into its default position because of the spring that biases it into that position. Next, the worker releases the handle 632, which causes the pin 640 to move back into the automatic position, thereby preventing the cliff-hanger from disengaging the upper corner casting.

[0059] The locking device 600(3) illustrates a vertical tandem lifting mode. In order to provide a better view of interior of the locking device 600(3), the housing component 602(1) has been hidden. The vertical tandem lift mode permits the locking device 600(3) to lock an upper and lower shipping container together. When so locked, the upper and lower shipping containers may be simultaneously lifted by a crane. To engage the vertical tandem lifting mode, a user pulls the handle 632 out and down. A swage 643 - a wider portion on the wire - interacts with the slot 635 in the mouthpiece 634 to hold the handle 632 in the position shown. With the handle 632 held in the position shown, the pin 640 is held in a position where both the upper hook member 652 and the hanger 670 are prevented from pivoting because the tab 662 and the tab 673 are blocked by the pin 640. The upper hook member 652 and the hanger 670 are thus locked into a closed position. In the vertical tandem lifting mode, the locking device 600(3) cannot disengage the corner castings of the upper and lower shipping container. To return the locking device 600 into the automatic mode, the user pulls the handle 632 to release swage 643 from the mouthpiece 634. [0060] Referring now to FIGURES 11A, 11B, 11C, and 11D, a discharge sequence for a locking device 700 is illustrated. Similar to the discussion of FIGURES 6A and 6B above, the discharge sequence will be discussed relative to a single locking device 700, but it should be understood that same discussion applies to the other three locking devices 700. Figure 11 shows four stages of the discharge sequence. To provide a better understanding of the movement of the components of the locking device 700, a sectioned view of the locking device 700 is shown next to a non-sectioned view.

[0061] Referring generally to FIGURE 11A, the locking device 700 is shown installed in an upper corner casting 702 and a lower corner casting 703. The upper corner casting 702 is associated with an upper shipping container (e.g., the upper shipping container 10 from FIGURE 1), and the lower corner 703 casting is associated with a lower shipping container (e.g., the lower shipping container 20 from FIGURE 1). The upper corner casting 702 includes an exterior wall 704, an ISO hole 706, and an interior wall 708. The lower corner casting includes an exterior wall 705, an ISO hole 707, and an interior wall 709.

[0062] The locking device 700 is shown just before the upper shipping container is lifted upwards. In this resting position, the upper corner casting 702 rests upon a load pad 710 of a housing 712. A hook 720 of an upper hook member 722 is shown in contact with the interior wall 708 and a hook 724 of a hanger 726 is shown in contact with the interior wall 708 on an opposite side of the ISO hole 706. A width T indicates a reach or span of the hook 720 and the hook 724. The width T is shown to be wider than a width of the ISO hole 706. A hook 728 of a lower hook member 730 is shown in contact with the interior wall 709. A width U indicates a cross-sectional width of the lower hook member 730 relative to the lower ISO hole 707. The width U is shown to be wider than a width of the lower ISO hole 707.

[0063] Referring now to FIGURE 11B, the locking device 700 is shown just after the upper shipping container begins to move upwards from the lower shipping container. Once the upper shipping container begins to move upwards relative to the lower shipping container, the width T between the hook 720 and the hook 724 has reduced slightly. The reduction in width T results from reactionary movements of the upper hook member 722. As the upper corner casting 702 moves upwards, FIGURE 1 IB shows that the hook 720 has moved a little bit closer to the left edge of the ISO hole 706 because the vertical load has tilted the upper hook member 722 in the clockwise direction. The lower hook member 730 has begun to tilt in a clockwise direction. As the lower hook member 730 tilts, a cam 736 on the lower hook member 730 is guided by first cam 732 of the housing 712. This rotation is caused by the interplay of the hook 728 with the interior wall 709 of the lower corner casting 703.

[0064] The first cam 732 also serves to make sure the hook 728 of lower hook member 730 remains engaged with the interior wall 709 when the upper shipping container experiences lifting on one side (e.g., a rolling event). During a rolling event, a locking device 700 of a side of the upper shipping container that does not experience lifting acts like a pin and prevents lateral movement of the upper shipping container relative to the lower shipping container. When lateral movement is limited, the lower hook member 730 will not be able to rotate or tilt far enough in the clockwise direction for the cam 736 to move from the first cam 732 to a second cam 734 of the housing 712. The orientation of the first cam 732 is such that the hook 728 remains in contact with the interior wall 709 to maintain a secured connection between the upper shipping container and the lower shipping container.

[0065] Referring now to FIGURE 11C, the locking device 700 is shown after continued upward movement of the upper shipping container. As the upper shipping container continues upwards, the upper shipping container also continues to move towards the right, and the lower hook member 730 continues to rotate clockwise. However, in FIGURE l lC, the cam 736 has now slid off of the first cam 732 and now follows the second cam 734. The second cam 734 permits the lower hook member 730 to continue to rotate to move the hook 728 out of engagement with the interior wall 709.

[0066] Referring now to FIGURE 1 ID, the locking device 700 is shown exiting the lower corner casting 703. In FIGURE 11D, the lower hook member 730 has rotated far enough in the clockwise direction to reduce the width U to a value that is smaller than the width of the ISO hole 707, and the locking device 700 may be pulled out of the lower corner casting 703.

[0067] Still referring to FIGURE 11D, it can be seen that a loading process works in a similar manner. As the upper shipping container is lowered towards the lower ISO hole 707, the lower hook member 730 is directed towards the lower ISO hole 707. The lower hook member includes angled faces to help guide the upper shipping container into the lower ISO hole 707.

[0068] Although various embodiments of the method and system of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Specification, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit and scope of the invention as set forth herein. It is intended that the Specification and examples be considered as illustrative only. For example, although dimensions of corner castings are standardized, dimensions of actual corner castings may vary because of manufacturing tolerances and/or because of wear from repeated use. One of ordinary skill in art will appreciate that the embodiments disclosed herein can be altered to work with corner castings of different dimensions. Such alterations may include changing one or more of a size or a shape of one or more components.